Electric discharge lamp starting device



H. J. M CARTHY ELECTRIC DISCHARGE LAMP STARTING DEVICE March 7,1944.

2 Sheets-Sheet 1 Filed Nov. 1, 1941 A mtl Fig. 4.

Henry JMO (iv-fl INVENTOR. BY 6 ATTORNEY March 7, 1944.

H. J. M CARTHY ELECTRIC DISCHARGE LAMP STARTING DEVICE Filed Nov. 1,1941 2 Sheets Sheet 2 Fig. 2

Fig 5 AT-ro my oi'therelayoi icui-ei.

Patented Mar. 7,1944

y 2,343,262 ELECTRIC mscmmen LAMP srmrmc I nrzvrca Danvers, Products ireJ. McCarthy, s rania Electric Application November 1. 1941, .Serial No.

3 Claims.

This invention relates to electrical circuit reing the electrodepie-heating period or electric gaseous discharge lamps.

An object of this invention is to provide a fluorescent lamp starterswitch which will not only operate to provide a pre-determined heatingFigure 1 invention;

2 is a schematic dia ram or the circuit Figure 3 is a schematic ofanother of other-alternate circuit.

In the operation or electric gaseous discharge tain, the relay trodepre-hea ing round the thermal relay shown in my co-pending applicationSerial Number 335,968, filed May 18,

consists of a therm'alreshown in the co-pending My present invention layof the general type is a projection of the relay of my lays and moreparticularly to relays i'or rezulaty of these regard, I have thro NTOFFICE Mass. assignmto Inc., a corporation nine down the relay supportI.

ting the conduction of heat from I find it more thermo-plastle andafinal coat of thermo-settinz In some cases,

it may be convenient to be advantageous. v A high resistance contact 45,such as nickel, lic strip 12 so tha sistance contact same reason, thelow resistance contact I! on from the contact i3 take place at about thebreaks away from the or an electric discharge device is accomplished byconnecting a resistance rod. a contact oi high contact resistance, and abimetallic strip with the relay as above-described. The wire 4 whichconnects the wire rod l with the lead-in wire 1 coming up from the basepin l has the resistance rod l9 mounted thereon. The bimetallic strip 20is fixed at one end on the wire 4 and runs along the longitudinal axisof the resistance rod l9 and adjacent thereto to a point beyond an endof said rod. The contact of high contact resistance, such as carbon,

2! is attached to this free end oi the bimetal 20 by the supporting clip22 and when the circuitthrough the relay is unenergized this contact 2iis closed with the wire 4.

In Figure 2, the lead-in wire 29 iromone end of the electrode 23 isconnected to one end of the power line from which the apparatus isoperated. An end of the other filament 24 is connected through asuitable ballast impedance, such as an inductance coil 32 to the otherend of the power line by the lead-in wire 30. The other ends of theelectrodes 23 and 24 are connected together by the lines 33 and 31respectively through the relay,

when the line voltage is'placed across the circuit terminals 29 and 40,the electrodes 23 and 24 of the lamp 26 will immediately start to heat.The heat conducted to the bimetallic strip I! of high contact resistancewill heat it suillciently to cause the bimetallic strip to break awayfrom the contact. rate resistance and a low resistance contact may wellbe used instead of carbon or other ,high, resistance contact, for ineither case, heat will 2 which supports the resistance c A sepaend ofthe bimetallic strip begcnerated to actuate the armature 20'. This timedthat it will normally same moment that the electrodes have beensufilciently heated to support the discharge across the lamp. Sincethere is about one-half line voltage across the resistance rod duringthe operation of the lamp, the heat,

conducted to the bimetallicstrip by the rod will cause the strip to takea position,,during the actual operation of the lamp, at a point abouthalf way between its normally closed position, with the high resistancecontact 13 and the low' resistance contact 18. Thus there is no dangerof the strip l2 cooling to a temperature where it would re-establish itscontact with the high resistance contact and thus renew the startingoperation.

If the current should be thrown oil, and immei diately thrown on againwithout sufllcient time: elapsing to allow the strip l2 to cool, or if,for any reason, the arc failed to strike when the strip i2 broke awayfrom the high resistance contact l3, the full line voltage would beacross the resistance l and the strip l2 would be heated and continue tobe deflected further away from breaking away is so the current passingnamely, intermittent glowing at the electrodes. To overcome this I havearranged the elements as shown in Figure i so that after the relay hascompleted several cycles oi operation in attempting to start the lamp,the relay will be cut out from the lamp and will no longer try to startit.

Under ordinary starting conditions, when the lamp starts after the firstor second electrode pro-heating interval, the resistance rod I! will notpass much current, it being shorted out and through the high resistancecontact 2i and the bimetal 20. However, when the lamp arc fails tostrike after several preheating intervals ior the electrodes thereofhave been provided therefor by the bimetal i2 and its associated highresistance and low resistance contacts, the high resistance contact 2!and the bimetal 20 will have passed current long enough to cause thebimetal 20 to become distorted sufilciently to cause the contact 2!attached at the free end thereof to break from its normally closedassociation with the wire 4. When this takes place, the current throughthe resistance rod I! will be enough to keep the bimetal 20 sufiicientiydistorted to keep the high resistance contact 2! on the free end thereofopen with respect to the wire 4.

,cut-out' has come into operation, will, be about the same as'lampvoltage, thus causing the free i2 to assume a position about halfway'hetwecn the high resistance contactfl3 andathelow resistance contactit. Thus,

not' only-will the operation of the relay in pro- "viding a successionof filament preheating interbe arrested, but, what is also of' greatimportance, the. several elements of the relay will not be subjected toexcessive voltages due to the abnormal condition of a failed lamp. Inthis way, the life of the relay is prolonged considerably. The severaldelicately, adjusted parts are not called upon to withstand anoveriailed lamp conditions. Although I have shown a of my invention inFigure 1, it must be understood, however, that some of the elementscontained therein may be changed in certain rethrough the resistance tedthe high resistance contact l3 until it struck the low resistancecontact of the lamp electrodes. If the lamp arc fails to strike when thebimetallic strip i2, now cooling,

low resistancecontact i6,

i6, thus short-circuiting the resistance rod i and starting thepre-heating tact 21 may the free end of bimetal will be obtained for inhowever, it. should be tension with'which the ,the carbon ooritact 2i orthe tension with which spects without departing from the spirit of theinvention. For example, the high resistance conbe fixed to the wire 4instead of to 20 and the same result I either case, the bimetal willbecome distorted sufficiently under abnormal lamp conditions to cause itto break the circuit 'therethrough and allow the current to flow iii. Ineither case, made certain that the bimetal i9 is closed to thecarboncontact .l' is closed with the wire 4 is greater than theitension withwhich the car- 'bon contact l3. lS 1C10S6d with the armature l2.

This is necessary to insure cutout from operating-under the preventionof the I normal lamp and relay operating conditions. Another embodimentof this-cut-out without departing from the spirit of the invention wouldbe the location of the contact of high contact resistance 2| above theresistance rod i9 instead of belov it as shown in Figure 1. In this casethe tension between specific embodiment insure relatively quickoperation of the cut-out under failed lamp conditions for when thecontact is located in this position it doesn't become fheated as quicklyas in the position illustrated in Figure 1.

Figure 3 shows another embodiment of my invention different from Figure2 only in the dottedline-enclosed cut-out unit. This cut-out can beutilized with various forms of starting relays whether they be thermalor glow. A glow relay, for example, is shown in my United States Patent2,277,708, issued March 31, 1942, on an application filed March 18,1940. In this figure, the resistance i9 is connected in parallel withthe imput terminals 35 and 36 oi the relay 31, and the contact 2| inthis case need not necessarily be of high resistance.

again permit said repetitive starting attempts: said second switchincluding a contact and a thermally responsive switching arm arranged toremain in closed relation with each other with the switching arm unmovedduring a plurality of said repetitive starting attempts, and tothereafter separate to break a lead to said repetitive switch andterminate the operation thereof, and a heating element, in operativerelation with said switching arm to automatically cause said separation,and in shunt with a series arrangement comprising said thermal arm, saidcontact,

a and said repetitive switch.

The cut-out assembly may be mounted on the wire 4 or on thecorresponding wire 5 or the other side of the relay without departingfrom the spirit of the invention. The schematic diagram of the relay asshown in Figure 2 illustrates this construction, while the constructionof Figure 1 is schematically illustrated in Figure 4.

What I claim is:

i. In combination with an electric discharge lamp and operating circuittherefor, a starting unit including: a switch, for relatively fastrepetitive operation in a series of attempts to start said" lamp,comprising heating means and, a thermally responsive switch member insuch arrangement that repetitive full energiaations of said heatingmeans consistently and continually cause said switch member to closesaid switch in like repetition; and a second switch, separate. distinct,and spaced from said repetitive switch,

, for relatively slow operation to automatically terminate saidrepetitive operation oi said repetitive switch and thereafter, upondeenergization of said circuit, to automatically reset itsel! to.

2. A starting unit for an electric gaseous discharge device, said unitcomprising: a plate-like base of insulating material; a panel-likeupright of insulating material mounted on said base; 'a pair of contactpins extending from one side oi said base; a pair of lead-in wires, eachconnected to one of said contact pins and extending from the other sideof said base; a switch assembly mounted on said upright in connectionwith said lead-in wires and including a heater element, a thermallyresponsive member mounted in heat-receiving relationship with saidheating element, and a contact assembly including a supporting arm and acontact member, with said thermal member in normally closed relationwith said contact member; and a second switch assembly connected withsaid first named switch assembly and one of said lead-in wires andincluding heating means and a hook-like thermally responsive memberarranged to short circuit said last named heating means whensufllciently heated thereby.

3. The combination of claim 1, and resistance means in series with, andin proximity to. the thermally responsive switching arm to heat the sameon passage of current therethrough.

J. MCCARTHY.

